Various wireless access technologies have been proposed or implemented to enable mobile stations to perform communications with other mobile stations or with wired terminals coupled to wired networks. Examples of wireless access technologies include GSM (Global System for Mobile communications) and UMTS (Universal Mobile Telecommunications System) technologies, defined by the Third Generation Partnership Project (3GPP); and CDMA 2000 (Code Division Multiple Access 2000) technologies, defined by 3GPP2.
As part of the continuing evolution of wireless access technologies to improve spectral efficiency, to improve services, to lower costs, and so forth, new standards have been proposed. One such new standard is the Long Term Evolution (LTE) (also referred to as the Evolved Universal Terrestrial Radio Access (EUTRA) standard) from 3GPP, which seeks to enhance the UMTS technology.
In a wireless communications network, information is communicated wirelessly between mobile stations and base stations. In response to information received in the downlink (from base station to a mobile station), the mobile station can send acknowledgment information to either provide a positive acknowledge (ACK) of successful receipt of the data, or negative acknowledgment (NAK) to indicate that the data was not successfully received. To improve reliability, a recent development of LTE proposed use of ACK/NAK repetition, in which a mobile station repeats the sending of an ACK or NAK in response to downlink information from the base station, to improve the likelihood that the base station receives the ACK or NAK. This may be particularly useful when the mobile station is in a region of a cell or cell sector that has relatively poor wireless conditions, such as at the edge of the cell or cell sector, or in another location associated with obstructions that may result in reduced signal strength or increased noise.
An issue associated with repetition of ACK/NAK is that in response to consecutively received pieces of downlink information, the acknowledgment information for such consecutively received pieces of information may collide, which may cause the base station to not reliably receive the acknowledgment information associated with the consecutively transmitted pieces of downlink information.